1. Field of the Invention
This invention relates to methods for processing certain species of wood before and/or after being cut into lumber, and more particularly to a method for preventing or deterring the warping, checking, staining, decay and susceptibility to insect damage of lumber and wood chips to improve their commercial value.
2. Problem
Red alder and birch, for example, are commonly used in furniture, cabinets and decorative woodwork. They are also used in building construction as trim, flooring, siding and paneling, but such use, as well as other structural uses, is limited because of the tendency of such wood to warp and check. When warping and checking, which is the cracking or separation of the wood lengthwise of the grain, are prevented or deterred, the quality of the wood is improved and the uses to which it can be put are increased, thereby increasing its commercial value. Such woods are also particularly susceptible to stain, blue mold and rot. Red alder is subject to red stain but birch and other species of wood are not. Further, the use of such wood in chip and pulp production is hampered because of the tendency of such wood to become infested with fungi and insects.
3. Prior Art
The Rice U.S. Pat. No. 1,732,419 discloses a process for treating wood intended to reduce warping, shrinkage and rot by immersing either logs or lumber which have not been previously dried in a sugar solution and boiling the solution until no further scum rises to the surface. To insect-proof or fungi-proof the wood Rice adds sodium fluoride to the sugar solution. Not only does the Rice process require the added expense of supplying the raw material sugar and considerable amounts of energy to boil the solution, but the added sugar promotes invasion by termites. As far as known such process has not been used commercially.
Although the Illingworth U.S. Pat. No. 1,025,628 is directed toward converting green wood of low commercial value, such as scrub pine or spruce, into a high grade elastic resilient wood, the process also purports to prevent the wood from decaying and protect it against attacks of insects. The disclosed process includes bucking the tree trunks into logs, soaking them in water until they are almost waterlogged, air-drying them in shade, sawing the logs into planks, soaking the planks in a saturated solution of lime water and covering them with unslaked lime. The process is very time-consuming and significant time and effort would be required to remove the excess unslaked lime, as well as to dry the essentially waterlogged wood. No known commercial use has been made of this process in the 68 years since that patent was granted.